The present invention relates generally to control mechanisms and more specifically to mechanisms for selectively establishing and maintaining the position of a control cable such as those used to control the position of small engine throttles, for example, in lawn mowers.
A variety of have been utilized prior to the present invention to control a small engine throttle cable, commonly known as a Bowden cable. These prior devices, which are usually of the linear slide type or the rotary lever type, typically provide a continuously adjustable cable setting and include some form of friction mechanism to maintain the set position after the control has been released. Although adequate for some applications, the conventional throttle control does not provide predetermined throttle setting positions, such as for engine starting, or for maintaining a preferred engine operating speed. Furthermore, a friction arrangement for holding the throttle control is not always reliable and, especially after of use subjected to the vibrations common to reciprocating engines, is subject to slippage. An unwanted change of engine speed can not only be annoying, but can pose a serious hazard, particularly if the engine should unexpectedly speed up.
Although control mechanisms have been developed which provide some form of stepped or ratchet action of the control level, such mechanisms typically either interfere with the desired ease of movement of the control, or provide inadequate control setting security. Such mechanisms suffer the further disadvantages of being complex in structure and expensive to manufacture.